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Hydronic Radiant Floor HELP "Taco X-Pump Block & Taco Radiant Mixing Block"

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Jkell777
Jkell777 Member Posts: 10
I have had issues with my radiant floor heat since I purchased my home late November of 2020. I am usually handy enough to make some head way on almost everything but this, I can't make any sense of what had previously been done and/or how to operate so, (other than me tinkering on it) the system is off and unplugged. I live in a rural area and only have one company that works with this type of system. But, this same company I refuse to use again as they been out and have charged me multiple times on my geothermal heating and air without fixing ANY of the problems. Leaving me to study and fix it myself.

I am currently doing a complete basement remodel (due to unfortunate flooding). The whole ceiling is exposed allowing me to fix, repair, and/or reroute my pex tubing, and to hopefully experiment to get this system dialed in. But now, I feel like the more I dig into this system and the more I learn, the more I feel like the original installers did not know what they were doing, leaving me more and more confused with no one to ask or help. So this has put a screeching halt on completing my basement remodel because I refuse to cover everything up since most everything to complete the system is already here.

I don't know if it helps but, I have a 3 story, 5,200sq. ft. house, built in 2007, with a daylight finished basement. All three levels of my home are very close with each other in square footage. My "Mechanical Room" is located on the far end corner of the basement which also houses all of my plumbing and components to my radiant system. My house is roughly 60ft long and 30ft wide.

The basement radiant floor is in slab and has 9 zones 1/2" PEX on the supply manifold, and 9 zones 1/2" PEX on the return manifold, and 1 Thermostat.

The main floor and the 3rd story are on 1 manifold and is an "In-Joist" application. On the supply manifold I have 3 zones 3/4" PEX and 1 zone 1/2" PEX. On the return side of the manifold I have 2 zones 3/4" PEX and 1 zone 1/2" PEX.

The whole system is "Closed Loop", and is power by a gas tankless hot water heater, a Taco X-Pump Block, and a Taco Radiant Mixing Block. I feel like I have watched countless videos and read countless articles with this but I haven't gotten far. I haven't seen one application where both the Taco XPB AND the Taco Radiant Mixing Block are used together, it always seems like it's one or the other but, I have both in mine.

I need detailed help with all of the system, like:
-Zones
-Layout
-Settings
-Operation

Some help and direction would be greatly appreciated so I can put my house back together. Thank you all so much!

An idea of how the PEX was originally ran


Don't mind the mess lol but, here's a direct look of what it was like


Tankless Water Heater "ONLY FOR FLOOR HEAT"


Taco XPB Top, Mixing Block Bottom


Mixing Block


Taco XPB




Manifolds & Zones. The top is the Main Floor and 3rd Story. Bottom is Basement


Under the Water Heater. Hot and cold are tied together. Shouldn't they be separate?

Comments

  • hot_rod
    hot_rod Member Posts: 22,387
    edited February 2023
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    The X block has a plate heat exchanger inside to isolate two seperate fluids. Possibly you have glycol loops?

    The other block is a temperature mixing system, an injection mix module, basically
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,206
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    Can You contact the original installer?   Taco tech support is excellent and depending where u are, you Taco Rep might come out and school you on the Taco products.  That's what I would do..Save u alot of time and aggravation.   Mad Dog
  • Jkell777
    Jkell777 Member Posts: 10
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    I’m not entirely sure if there was glycol in the system or not. Is glycol needed? To my understanding, glycol is to keep it from freezing when the weather is cold but, this whole system is plumbed and ran indoors. Also, those two blocks are plumbed together and when we bought the house both of the blocks were plugged in. I don’t know if I’m just thinking way to in depth or what but this system has been a huge headache! lol. 
  • hot_rod
    hot_rod Member Posts: 22,387
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    Jkell777 said:

    I’m not entirely sure if there was glycol in the system or not. Is glycol needed? To my understanding, glycol is to keep it from freezing when the weather is cold but, this whole system is plumbed and ran indoors. Also, those two blocks are plumbed together and when we bought the house both of the blocks were plugged in. I don’t know if I’m just thinking way to in depth or what but this system has been a huge headache! lol. 


    It’s hard to know the intention of the original installer/ designer. I don’t see a reason to use the HX block unkes# you are isolating a glycol loop, or possible connected to a domestic water heater as the source.
    The HX is fairly small in those blocks, so unless you have a fairly high temperature on the one side, it may not cover the entire load of a home that size?

    You might consider a piping redo and update on a system that age. get rid of the tankles# water heater as the hydronic heat supply would be a good step😚
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Jkell777
  • Jkell777
    Jkell777 Member Posts: 10
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    The original installers are the only place close to me that handles radiant. They also specialize in geothermal heating and air which I also have. This is the same company I refuse to give any more business to. They were called out to fix my heating twice in the winter because only one of my three stories would heat. They charged me both times (both times I was gone) and my wife paid them both times. They said that everything is working how it should and left, even though the main floor in my house was 38 degrees. They did the same to me in the summer months when I had no A/C but told me I needed a whole new system because my equipment was shot from being on an open loop system. So they said it needs to be closed loop and all new equipment, roughly $100k. I fixed it myself by replacing an auto valve that was stuck. That’s the only one close to me that deals with floor heat so my hands are a bit tied. I haven’t tried calling Taco though. That definitely will be something else I will resort to!
  • hot_rod
    hot_rod Member Posts: 22,387
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    That looks like a Buderus boiler, not a tankless water heater, how old is it?
    You have a suspended tube installation on that upper level, it may need to run 140 or hotter, the slab much lower. So you need at least two temperatures.

    Has the system heated adequately on the coldest days.

    Is the heat pump still involved?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2
  • Jkell777
    Jkell777 Member Posts: 10
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    I’m assuming it was put in when the radiant was installed. So that was most likely in 2007. I have two heat pumps, but they are only hooked up for HVAC not radiant. The only equipment involved for the floor heat is the Taco equipment, and the Buderus boiler. From my understanding is that the boiler temp needs to be set (like you said) 140 degrees. But, from there I set the pump block and mixing block temps. I’m confused as to why there is both. I’ve read the manuals and in my head they seem like they are close to the same thing. 
  • hot_rod
    hot_rod Member Posts: 22,387
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    What is it you are trying to fix? It looks to me to be a boiler dedicated to radiant heat. I don’t see a potable water tie in?

    If it is under performing a few easy to check.


    Disassemble the Honeywell air purger top, see if the wire mesh inside is plugged.
    On the manifolds by the red handle valve, under that brass hex is also a strainer, remove and check those also. If the flow is being reduced thru plugged strainers the heat output will, drop, maybe considerably.

    I can’t answer why they used a HX block and a standard block. Seems the boiler could operate at the temperature that suspended tube requires, one mix down for the slab zones.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jkell777
    Jkell777 Member Posts: 10
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    I have never had this system work since I have owned this house. And by two temperatures… is that the reason between for the two blocks?
  • hot_rod
    hot_rod Member Posts: 22,387
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    It doesn’t heat at all, or doesn’t heat adequately?
    Yes both those blocks are capable of temperature mixing, one has a heat exchanger, for some reason.

    Ideally there was a heatload calculation and design done at the first install. Wirsbo provided designs when they promoted that suspended tube design and concept. I don’t suppose there is any documentation lying around.

    A big difference between not working, ever. Or not working properly 18 years later.
    If the fluid has slugged from that aluminum boiler, good chance the heat exchanger in the radiant block is somewhat or mostly plugged.

    Many, many things to check from flow to control settings.
    .
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jkell777
    Jkell777 Member Posts: 10
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    So yes, the boiler is dedicated just for the radiant heat. I guess first off, what I’m trying and have been trying is to get what I have operational. But, it’s even more crucial for me now since everything is exposed due to the remodel. It hasn’t worked as in people that I have known that have radiant heat say it’s amazing. There is not a spot in my home that you can tell a difference when it’s on except it’s another thing plugged in drawing power. 

    I feel like the way it was ran, the runs are way too long, the tubing between the joists are spaced to far apart, most of it is not touching sub floor, and most of the the joist bays were un insulated.

    So far, I’ve spaced the lines closer, I’m adding heat transfer plates, and I’m going to insulate. I’m not understanding how to properly map/ design the tubing layout, and I don’t want to cover anything up until I trial and error and test. 
  • Jkell777
    Jkell777 Member Posts: 10
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    And unfortunately I don’t have any of the original documentation. 
  • Jkell777
    Jkell777 Member Posts: 10
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    And if more pictures would be helpful of different angles I can definitely do so! 
  • hot_rod
    hot_rod Member Posts: 22,387
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    Or you could start at the beginning, instead of making random changes.

    A room by room heatload calculation would be the only way to know if the system will work as built. The suspended tube systems, can, did, do work.

    They work by warming the joist bay which in turn heats the floor above. The only requirement is to warm the floor enough ambient temperature to heat the space. Insulation below is a must, rim joist insulation detail is critical.

    But without a road map, heatload design, you may be changing things that do not need to be changed?


    Did the previous owner live there 13 years without heat? I doubt it.

    The suggestions I made above would be more practical then changing the tube installation, which may not solve your problems if the system is not getting proper flow and temperature to cover the loads, adding transfer plates may be a tedious waste of time and money. Adding them in some areas and ni5 others will complicate supply temperature requirements, over temperature some areas.

    Aluminum block boilers like yours have a tendency to sludge up inside. Often a power flush brings them back to a proper operating condition, another simple task without buying or changing anything.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jkell777
    Jkell777 Member Posts: 10
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    That’s kind of what I was thinking. I’m the 3rd owner but the original owner is my neighbor. He did mention that they originally heated the basement with the radiant but didn’t mention anything else. It’s also weird to me that the PEX tubing runs everywhere but the master bedroom, bathroom and closet (like it got skipped)? What’s your thoughts on the plumbing on the picture of underneath the boiler? I can’t make sense of the “HOT AND COLD” tied together. No valve or nothing, just straight plumbed. It doesn’t make any sense to me. 
  • TonKa
    TonKa Member Posts: 104
    edited February 2023
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    You mentioned geothermal heat *and* you have a boiler...

    If you actually do have geothermal, this is probably why you have the Taco X Block. Your geothermal loops are probably using glycol.

    I think what you are referring to as "HOT AND COLD" are the boiler supply and return. They connected to closely spaced tees. This is normal in a primary/secondary piped system.

    Your Taco Mixing block probably is there because one section of your system needs lower temperature water than what the boiler is producing. My guess is your basement slab.

  • hot_rod
    hot_rod Member Posts: 22,387
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    One connection on the manifold is marked "master" looks like a 3/4 tube so it maybe feeds a manifold upstairs somewhere? It has red marker tape, probably the other end does also.

    The connections below the boiler are primary secondary piping, they are fine.

    So only the basement radiant worked? The upper levels were heated by the GEO perhaps?

    The question remains, did the entire radiant system ever work? Did it heat the home adequately.
    The original owners should be able to answer that simple question. If the answer is no, you have a much bigger task ahead :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jkell777
    Jkell777 Member Posts: 10
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    The radiant system has not ever worked since I have owned the home. I’m the third owner. The original owner mentioned that used to be the primary way to heat the basement but, it has never worked for me. The geothermal heat pumps are only running my heating and air, and is an open loop system not connected to the radiant flooring. The radiant flooring is closed loop system and the heated floors is the only that equipments function. So the upper levels have nothing to do with the geothermal. 

    This picture is what I’m referring to when I say “Hot & Cold”. This is underneath the boiler. I am confused on why this is plumbed this way because how my brain works is “cold water goes in, boiler makes water hot, hot water comes out”. But between the hot and cold there is no valve or anything. It’s just straight piped mixing the hot and cold? 
  • hot_rod
    hot_rod Member Posts: 22,387
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    Your finger has landed on closely spaced tees. This is a piping method that assures both the boiler and distribution piping can always get proper, sufficient flow rates. From what I see your system is properly piped, that is not the problem, move on🥴

    Lack of performance in my mind may be due to improper, inadequate flow rates, possible miss adjusted control settings on those mixing blocks 

    You have a hydronic puzzle, each piece needs to be examined to find the roadblock 

    This takes some hydronic knowledge and tools to take some measurements while the system operates

    Most hydronic gurus agree that 10-15 btus per square foot is about all you will get from that suspended tube type installation. IF it is insulated properly, R 30 below it, for example

    However if the heat load of the room is more than 15 btu/ sq ft, I think you already have the answer. The radiant system will not provide the amount if heat the home requires

    If the system has never heated the home adequately it could be it was never designed, sized, installed properly.

    A room by room heat load calculation is the way to confirm this.  No sense in firing the parts cannon at a system that will not, cannot get the job done

    put pencil to paper before you spend any more time or money on the project!
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,206
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    Yeah. That's A Buderus GB-142.   It sounds like you need a field visit by a pro from here to get an honest assessment and plan of resolution. And, as I said earlier, why not get Taco rep out there.. that is what they do and are eager to help. Mad Dog